The Caller - S9-E10
Continuity mistake: At the beginning, a St Louis couple has reported their son missing. At the FBI briefing, the agents are told that the boy's mother tucked him in at 10:00pm. A few minutes later, we hear the radio call over footage of police at the home, and the dispatcher says "Last seen at 2100." That's 9:00pm, not 10:00pm. (00:03:00 - 00:05:00)
Chosen answer: Black SUVs are common police, military and dignitary vehicles around the world. It is not too much to assume they could be rented or owned by the police forces in the areas.
kristenlouise3
Other people have explained it but fore more information, federal cars would most likely be brought to the airport from the nearest agency, so they can drive out to their locations especially in rural situations.